1. Field of the Invention
The invention relates to a Coriolis mass flowmeter having at least one bent measuring tube, having a carrier bridge extending between the inlet side and outlet side end of the measuring tube and fixing the measuring tube ends, having at least one oscillation generator for exciting the measuring tube to oscillations, having at least one oscillation sensor for recording measuring tube oscillations, having an evaluation unit for evaluating the measuring tube oscillations recorded by the oscillation sensor, and having at least one conductor arrangement for transmitting the recorded measuring tube oscillations to the evaluation unit, wherein the measuring tube has a central curve and the measuring tube extends, at least with its central curve through at least one opening in the carrier bridge from the inner area of the carrier bridge out of the carrier bridge into the outer area of the carrier bridge, and wherein the oscillation sensor is attached to the measuring tube outside of the carrier bridge, namely outside of the closed section that is limited by the carrier bridge and the section of the measuring tube running outside of the carrier bridge.
2. Description of Related Art
Coriolis mass flowmeters are known in a plurality of designs in the prior art. Mass flowmeters that operate using the Coriolis principle usually have at least one oscillation generator, with which the measuring tube is excited to oscillation—or possibly also for exciting several measuring tubes to oscillation—as well as, often, two oscillation sensors, with which the desired oscillation or the desired oscillations of the measuring tube are recorded. The oscillation sensors are usually attached on the inlet and outlet ends of the measuring tube. Without flow, the signals of the two oscillation sensors are essentially in phase. With mass flow, differently directed Coriolis forces result on the inlet and outlet ends, which lead to a phase shift between the deflections and thus between the two signals of the oscillation sensors, wherein the phase shift is proportional to the mass flow within the measuring tube.
The oscillation generator and the oscillation sensors are mostly constructed so that they have a permanent magnet as well as a coil in order to transmit oscillations to the measuring tube electrically or to record oscillations of the measuring tube.
In order to make connection of the Coriolis mass flowmeter to the process easily possible, carrier bridges have an input flange and an output flange, into which the measuring tube is inserted with its ends. The measuring tube is attached in the carrier bridge so that the measuring tube can essentially only be moved into oscillation outside the carrier bridge due to the effected fixation. Node plates are often used in order to exactly specify the oscillation zero point.
From experience, Coriolis mass flowmeters having a bent measuring tube or having several bent measuring tubes, one oscillation generator, two oscillation sensors and a carrier bridge are known to the applicant, in which the oscillation generators are located within the closed area that is limited by the carrier bridge and the section of the measuring tube or measuring tubes running outside the carrier bridge. In Coriolis mass flowmeters known from the prior art, the conductor arrangement, with which the electric measuring signal recorded by the oscillation sensors is transmitted to the evaluation unit, is sometimes guided along the measuring tubes and attached to the measuring tubes. Since the measuring tubes are carriers of the measuring signal in the form of oscillations, it cannot be ruled out that guiding the conductor arrangement along the measuring tube influences measurement, in particular, guiding the conductor arrangement affects the accuracy of the flow measurement as well as the series spread of the measuring device behavior. Among measuring tubes with small cross sections, guiding the conductor arrangement along the measuring tube in the shown manner can have adverse effects, which is naturally not desirable.